Process for making fibers



UNITED STATES PATENT OFFICE.

BUDOLF IRON, OF GERSAU, SWITZERLAND.

PROCESS FOR MAKING FIBERS.

1,376,285. No Drawing.

To all whom it may concern:

Be it known that I, RUDOLF KRoN, a citizen of the Swiss Republic, and resident of Gersau, Canton of Schwyz, Switzerland, have invented anew and useful Process for Making F-ibers for the Manufacture of Rough Pasteboard Suitable for Saturating with Tar for Roofings, Linings, or the like, of which the following is a full, clear, and exact specification.

In producing raw material for maklng the rough pasteboard from which roofings and linings, commonly saturated with bituminous material,'are manufactured, rags of wool, cotton or jute, or of half wool, or waste wool or waste cotton, are ground to a long fibered pulp which is then made into an endless sheet on the sieve of an ordinary paper-making machine, whereafter water is pressed from the sheet, which is finally dried on drying cylinders. In order that the pasteboard produced may be suitable for the purpose in question it should be absorbent, not easily broken or torn and durable; for these properties there must not be added to the jute, wool or cotton fibers more than 10 per cent. of strong waste paper, while short wood fibers (whether white or brown) or straw fibers cannot be used at all for this purpose, owing to their entirely insufficient firmness or consistency and their much too low capacity for absorbing tar or bituminous material.

Fibers of sulfite cellulose or of soda cellulose, which are sufiiciently strong, can only be used after having been first washed with care in order that they may not become destroyed by the traces of acid or salt which they contain. Therefore, these fibers are too expensive; they felt also together very densely so that they are not easily saturated by the tar or bitumen.

This invention relates to a process for making fibers applicable to the manufac- Specification of Letters Patent.

Patented Apr. 26, 1921.

Application filed September 18, 1919. Serial No. 324,555.

ture of rough absorbent pasteboard useful for saturating with tar, the fibers being cheap, felting together not too densely and, therefore, forming an absorbent spon y sheet, andat the same time resisting sufit ciently breaking or tearing, and of great durability when used as roofing. For this purpose, wood in the form of logs or other large pieces, preferably coniferous Wood (pine or fir), or another ligneous or strongly siliceous plant, is converted into fibers Without use of alkali lyes or acids-b simply boiling it with water, or steaming 1t, and subsequently rolling it out, crushing and grinding it, so as to obtain the natural cellulose fibers without deterioration and not weakened by chemical agents; the product is the most economical and the best substitute for cotton, wool or jute fibers for the purpose in uestion.

What claim is: A process for making cheap fibers which felt together not too densely, producing an absorbent, spongy sheet sufliciently strong to breaking and tearing strains and sufliciently durabl for application to the manufacture of rough pasteboard to be saturated with tar or bitumen for roofing, linings or the like, which process consists in converting wood in the form of logs or other relatively large pieces, or ligneous or strongly siliceous plants into fibers-without use of alkalies or acids-by boiling with water, or by steaming, and subsequently rolling out, crushing and grinding, so as to obtain the natural cellulose fibers without deterioration and not weakened by chemical agents.

In witness whereof I have hereunto signed my name this 2nd day of September 1919, in the presenc of two subscribin witnesses.

' RUDOL KRON. Witnesses:

MARIA C. GUISER, AMANDA RITTER. 

